1. Field of the Invention
The present invention relates to a method of treating Tourette's syndrome and other related central nervous system (CNS) disorders.
2. Description of Related Art
Tourette's Syndrome (TS) is an autosomal dominant neuropsychiatric disorder characterized by a range of neurological and behavioral symptoms. Typical symptoms include (I) the onset of the disorder before the age of 21 years, (ii) multiple motor and phonic tics although not necessarily concurrent, (iii) variance in the clinical phenomenology of the tics, and (iv) occurrence of quasi daily tics throughout a period of time exceeding one year.
Motor tics generally include eye blinking, head jerking, shoulder shrugging and facial grimacing. Phonic or vocal tics include throat clearing, sniffling, yelping, tongue clicking and uttering words out of context.
The pathophysiology of TS is currently unknown. However, it is believed that neurotransmission dysfunction is implicated with the disorder. Diseases that are often associated with or accompany TS include Attention Deficit Disorder with or without Hyperactivity, obsessive or compulsive behaviors, learning disabilities, and behavior and sleep problems. Other CNS disorders commonly associated with neurotransmission dysfunction and, particularly, cholinergic deficiency include presenile dementia (early onset of Alzheimer's disease), senile dementia (dementia of the Alzheimer's type), Huntington's chorea, tardive dyskinesia, hyperkinesia and mania.
Current treatment for TS mostly includes the administration of medications which are prescribed for neurotransmitter (i.e., choline, dopamine, adrenerine, and serotonin) disorders, including haloperidol, pimozide, clonidine, clonazepam, and nitrazepam. Compounds that modulate the activity of various receptors have been suggested as treatment due to a decreased number of receptors (particularly acetylcholine (Cosford et al., U.S. Pat. No. 5,686,473) and D.sub.2 dopamine receptors (Kerrigan et al., U.S. Pat. No. 5,767,116)) in the brains of patients suffering CNS disorders. Additionally, nicotine pharmacology has been suggested in suppressing TS. (Bencherif et al., U.S. Pat. No. 5,731,314). It has also been suggested that TS is caused by the supply of tryptophan to the brain, and TS symptoms have been treated by increasing and decreasing tryptophan supply to the brain. (Richardson, U.S. Pat. No. 5,670,539) It has also been suggested that treatment with nitric oxide synthase inhibitors in dopaminergic systems to reduce the amount of nitric oxide in the brain is useful in reducing the symptoms of TS.
Stimulants such as methylphenidate and dextroamphetamine may be prescribed for hyperactivity and Attention Deficit Disorder, but often increase the tics of Tourette's syndrome. Fluoxetine and clomipramine are often prescribed to relieve obsessive and compulsive symptoms. Other side affects from medication can include fatigue, motor restlessness, weight gain, social withdrawal, depression, cognitive impairment, and impotence. Thus, there is a continuing search in this field of art for improved methods for relieving the symptoms of TS and the associated afflictions without the side affects.